SnS Micro/Nanocrystals with Urchinlike Architectures for Capture of Au(III), Pt(IV), and Pd(II)

The capture and recovery of precious metals like platinum, palladium, and gold from mine wastewater or secondary resources has raised concerns owing to the necessity and significance of environmental protection and sustainable development. Although two-dimensional layered materials exhibit great promise for capturing and removing noble metal ions due to highly exposed active sites, the laminar structure of two-dimensional materials with high specific surface energy readily induces the accumulation of nanosheets and structural damage during ion adsorption reactions, greatly impeding their practical application. Herein, for the first time we developed a one-pot synthetic strategy to construct hierarchical SnS micro/nanocrystals with three-dimensional (3D) and urchinlike architecture in which the SnS nanosheets generate on the surface of the SnS microcenter. Interestingly, altering the content of polyvinylpyrrolidone (PVP) can modulate the morphology of SnS, including nanoparticles, nanoflakes, urchinlike microstructure, and flowerlike microstructure. The hierarchical urchinlike SnS materials were applied to capture the precious metal ions. As expected, high selectivity and efficient capture were achieved with an order of Au3+ > Pd2+ > Pt4+. Specifically, the as-synthesized urchinlike SnS maintains high efficiency for the capture of Au3+, Pt4+, and Pd2+ under strong acid conditions. In addition, the excellent capture capacities for Au3+ (793.7 mg g–1) and high distribution coefficients (Kd) of 1.97 × 106 mL g–1 place the SnS at the top of the range of materials known for capture. Fast adsorption kinetics analysis displays a kinetic constant of 9.103 × 10–6 g mg–1 min–1 according to the second order kinetic reaction equation. There was no obvious morphology change for the as-prepared SnS material after the capture of noble metal ions, suggesting its robust stability. The 3D SnS micro/nanostructure was thus promising for efficient separation, high sensitivity detection, and removal of the noble metal.